Apparatus for manufacturing textured filament yarns



May14, 1968 v E. K. MQNTO H ET AL 3,382,658

APPARATUS FOR MANUFACTURING TEXTURED FILAMENT YARNS Original Filed Jan.26, 1965 INVENTORS P. 71 HOWSE, JR. E. K. MQIN TOSH ATTORNEY UnitedStates Patent 3,382,658 APPARATUS FOR MANUFACTURING TEXTURED FILAMENTYARNS Euell K. McIntosh and Paul T. Howse, Jr., Pensacola, Fla.,assignors to Monsanto Company, a corporation of Delaware Originalapplication Jan. 26, 1965, Ser. No. 428,088, now Patent No. 3,343,364,dated Sept. 26, 1967. Divided and this application May 16, 1967, Ser.No. 638,978

4 Claims. (Cl. 57-34) ABSTRACT OF THE DISCLOSURE T wist-curled texturedyarn is treated to render the same more voluminous and dimensionallystable. In such treatment the textured yarn is fed from a source ofsupplyto a point of packaging. During its travel the yarn is relaxedwhile it is being heated in at least two separate stages. Between eachof the stages, the yarn is stretched while'the same is being cooled.

This application is a divisional application of application Ser. No.428,088, filed Jan. 26, 1965, now Patent No. 3,343,364.

Background of the invention The present invention relates to themanufacture of textured filament yarns. More particularly, it relates tothe manufacture of twist-curled textured filament yarns having anexcellent balance of bulk and stretch qualities.

Continuous multifilament man-made yarns have outstanding strength butlack absorbency, cover, stretch and insulating power in fabrics found inyarn spun from staple fibers. Many ways are known for imparting some ofthese desirable properties of spun yarn to continuous filament yarn. Inthe trade the term texturin'g has been applied to various techniques forimparting such properties to filament yarn. Virtually all texturingprocesses depend on the susceptibility of thermoplastic yarns to beheat-set when deformed and to have the lasting tendency to retain thedeformed shape.

There exists a recognized interrelationship between certain sought afterproperties in textured yarn. Bulk and stretch are both desirablequalities in textured yarns. Stretch textured yarns are characterized byhigh elongation and rapid recovery but show only moderate bulk per unitweight. On the other hand, certain yarns are tailored to exhibit highbulk; but the gain of such properties results in sacrifice to stretch.

To obtain a balance of bulk and stretch it is known to heat-setpreviously imparted crimp in stretch yarn in a partially extendedcondition. The resulting modified stretch yarn has found acceptance in avariety of fabrics.

Stretch yarns are textured so that they are twist-curled. Twist-curledtextured yarn is a lively-stretch yarn characterized in that thefilaments in a relaxed state exhibit a continuous coil. Ordinarily,twist-curled textured yarn is made by a three step process. In the firststep, the yarn is twisted a desired amount. While in the twistedcondition, the yarn is heat-set during the second step. That is, theyarn is heated and cooled while twisted so that the twist shape ispreserved until the yarn in a different shape is again heated to orabove the setting temperature. Finally the yarn is detwisted. The twistimparted and set in the yarn can be a true twist or a false twist. Foreconomic reasons, the latter type of twist is preferred. False twistingis a well-known method by which the yarn is twisted 'and untwisted inone operation, the yarn being heat-set when twisted.

Twist-curled textured yarn has the tendency, commonly called torque, toreturn to the twisted condition extent 3,382,658 Patented May 14, 1968when it was heat-set. The presence of torque in the yarn gives rise tocertain handling problems in converting the yarn into fabric. In theknown processes for obtaining a balance of bulk and stretch as referredto above, sufiiciently elevated temperatures are employed during theheat setting of the yarn in the partially extended condition such thatthe torque is virtually destroyed.

It has been found that one can obtain an improved balance of bulk andstretch by heating and cooling twistcurled textured yarn underparticular conditions that do not totally nullify the torque of the yarnbut do render the yarn more voluminous and dimensionally stable.

It is an object of the present invention to provide for the manufactureof twist-curled textured yarn having an excellent balance of bulk andstretch.

Another object is to provide a method for treating twistcurled texturedyarn to render same more voluminous and dimensionally stable withoutdestroying the torque thereof.

Another object is to provide apparatus for treating twistcurled texturedyarn.

Yet another object is to provide a twist-curled textured man-madethermoplastic continuous multifilament yarn having an excellent balanceof bulk and stretch.

In accordance with the method of the invention twistcurled textured yarnis longitudinally fed from a source to a point of packaging. The yarncan be a single end or can be composed of a plurality of ends,preferably of opposite and substantially balanced torque. Between theyarn source and packaging, the yarn is relaxed about 5-30% while it isbeing heated, preferably with steam, in at least two separate stages.The temperature attained by the yarn during the heating step is at least0., preferably about ll0-175 C. Between each of the multi-stage heatingsteps, the yarn is stretched without being permanently attenuated whilethe same is being cooled to at least 50 C. or less, preferably 30-125 0,lower than the temperature attained by the yarn during the heatingsteps.

Generally speaking, apparatus for treating the yarn includes means forfeeding twist-curled textured yarn at a predetermined first speed andmeans for forwarding the yarn at a predetermined second slower speed. Inthe yarn path between the feeding means and the forwarding means, meansis provided for heating the yarn. Guide means are used for returning theyarn'a plurality of times from the forwarding means through a coolingmedium to the feeding means. Finally, a suitable take-up device isemployed to collect the treated yarn in a uniform manner.

First, -a source of twist-curled filament yarn is provided. The yarn iscomposed of thermoplastic man-made continuous monofilament ormultifilaments. It is necessary that the yarn be textured so that it istwist-curled. As indicated above, twist-curled textured yarn is a livelystretch yarn made by heat-setting twist therein and reducing the twistwith the result that the yarn exhibits a torque. When the yarn isheat-set so as to twist-curl texture the same, it is preferred that thefilament yarn has a twist of about 30150 turns per inch. The temperatureat which the yarn is heat-set will vary in accordance with thecomposition of the yarn. For Nylon-66 yarn a heat-setting temperature ofISO-250 C. has been found to give good results. For nylon-6, a lowerheat-setting temperature can be employed.

The twist-curled yarns are of textile grade and are man-made byconventional procedures. Nylon is the preferred polymer from which theyarn is made. Nylon is is a long-chain synthetic polymeric amide whichhas recurring amide groups as an integral part of its main polymerchain. Specific types of nylon in addition to the two previouslymentioned types include nylon-610, nylon-4, nylon-7, nylon-l1 andfiber-forming polymers thereof. Other thermoplastic fiber-forming resinsfrom 3 which the yarn can be made include polyethylenes, polypropylenes,polyurethanes, polymers of vinyl acetate and vinyl chloride, polymers ofacrylonitrile, linear polyesters of aromatic dicarboxylic acids anddihydroxy compounds such as polyethylene terephthalate, and others.

When originally heat-set, the yarns forming the source of twist-curledtextured filaments for the process of the present invention can have aZ-twist or S-twist. Preferably Z-twist-curled yarn is plied withS-twist-curled yarn with the result that the torque forces of the yarnsoppose each other so that the resultant thread bundle appears to betorqueless.

The twist-curled textured filament yarn is fed from the source of supplythrough a heated zone at a controlled speed to provide a predeterminedheating and overfeeding of the yarn therethrough. This can beaccomplished by employing two pairs of yarn forwarding rolls, the secondpair of which is operated at speed such that the yarn is moved therebyat about 70-95% of the linear speed at which the yarn is fed by thefirst pair of rolls. Between the two pairs of rolls the tension of theyarn is reduced corresponding to the selected percent of overfeed whilethe yarn is heated preferably to 1l0-175 C. The temperature that theyarn attains While relaxed be tween the two pairs of rolls is controlledby correlating the temperature of the heating means used to heat theyarn and the speed at which the yarn moves through the environment ofthe heating means.

The heating of the yarn while relaxed is preferably accomplished by theuse of pressurized steam. Thus, the yarn is passed through a steamingchamber or the like with a controlled overfeed and speed properlycorrelated with the temperature of the steam.

After being heated under such controlled conditions, the yarn is fedthrough a cooling zone at a controlled increased speed to provide apredetermined cooling and stretching of the yarn. This can beaccomplished by guiding the heat-treated yarn from the second set offorwarding rolls back to the first set of forwarding rolls through apath remote from the influence of the heater. Ambient room temperatureis ordinarily sufiicient to cool the yarn. However, the yarn may becooled in a more positive manner such as using a coolant at this pointin the process. As can be seen, the yarn undergoing cooling is moved ata speed equal to substantially that at which the yarn is forwarded tothe heating zone. Since the first set of rolls is normally operated atspeed -30% greater than the second set, the yarn is lengthened by a likeamount as it is being cooled. The yarn is usually tensioned during thecooling step at about 0.10-0.40 gram per denier.

After being heated and cooled in the two just described zones, the yarnis relaxed at least one more time while it is being heated under similarand controlled conditions. This is accomplished by passing the yarnthrough the same or like heating zone under similar conditions. If theyarn is heat treated for the third or additional time, the yarn iscooled while being stretched between each heat treatment while employingthe same or similar conditions used in the above-described cooling zone.

Finally the yarn is packaged in a uniform manner using any suitablepackage builder.

Description of the drawing The attached drawing illustratesschematically apparatus for carrying out the invention.

Thermoplastic yarn is indicated by numeral 1. The yarn is composed of aplurality of ends of man-made filaments that have been molecularly drawnand twist-curled textured. When textured, individual ends of the yarnhad been highly twisted with the twist being heat-set in a conventionalmanner and then being removed. Yarn ends having opposite and equaltorque movements were plied using a low plying twist to form a balancedply yarn construction. It is not necessary that the textured yarn to betreated have a balanced ply, say of an S-twist-curled end and aZ-twist-curled end. These ends can be processed alone, although it ispreferred to provide as a source of yarn to be treated yarn composed ofmultiple ends of opposite and equal torque moments. As shown, yarn 1 iswrapped on a holder 2 in the form of a package 3. The holder may berotated to insert additional twist prior to treatment. If desired. Thesource of the yarn need not be from such a package since it is sometimesdesirable to use yarn being directed from a texturin g machine withoutany intermediate packaging.

Yarn 1 is withdrawn over an end of holder 2 led through guide 4 and overguide 5. Other guide arrangements, of course, can be employed. Fromguide 5 the yarn is passed through a rotatably arranged thread advancingmeans comprised of two nip-forming rolls 6 and 7 that are used towithdraw the yarn and to supply same for subsequent treatment at acontrolled supply rate. Roll 7 is shown to be positively driven throughshaft 8 coupled with suitable driving means not shown.

From rolls 6 and 7 yarn 1 is fed downwardly through heating zone A to alower pair of nip-forming rolls 9 and 10 that are used to move the yarnthrough the heating zone at a controlled overfeed. The lower pair ofrolls rotate at a predetermined peripheral speed less than theperipheral speed of the upper pair of rolls. Thus, the yarn goingthrough the heating zone is under low but controlled tension. Thetension allows the twist-curl texture to be partially manifest. However,the tension will not ordinarily be so low that the yarn is permitted tofreely relax such that the full bulkiness of the yarn is realized beforeheat treatment. Roll 10 is positively driven through shaft 11 coupledwith suitable driving means not shown.

Between the two sets of rolls a steam chamber 12 is employed. Thechamber has a yarn entry port 13 and a yarn exit port 14 between whichsteaming chimney 15 extends. A source of steam (not shown) is provided.The steam is moved through a conduit 16 to a plenum chamber 17. Thesteam escapes into the chamney through a plurality of openings extendingbetween the chimney and the chamber. The steam exhausts through ports 13and 14 with some of the steam being returned to the source throughconduit 18. Insulation in chamber 12 minimizes heat loss to thesurroundings.

From rolls 9 and 10 the yarn is led through cooling zone B over guides19 and 20 to be returned to the nip of rolls 6 and 7. Since the latterrolls are operated at a faster speed than the former, the yarn will beextended by an amount proportionate to the difference in the peripheryspeeds thereof. As the yarn passes from the bottom rolls to the upperrolls the yarn is attenuated; but the extension of the yarn is below thepoint where the yarn would be elongated resulting in a permanentreduction in the cross-sectional area of the yarn.

Again the yarn is fed downwardly through the heating zone under the sameheat and tension conditions employed in its first pass therethrough. Theyarn may be packaged at this point or, as illustrated, the yarn can bepassed through cooling zone B and heating zone A additional times.Finally the yarn is led through guide 22 and is taken up in an orderlyarrangement by a suitable type of package builder. As shown in thedrawing, the yarn is taken up by a ring twisting assembly comprising abobbin 23 adapted to be driven by belt 24 and a verticallyreciprocatable spinning ring 25 carrying a ring 25'. Thus, the yarn istwisted a selected amount as it is wound on the bobbin. When additionaltwist is not desired, a coner or other types of builders can be employedin place of the ring twister.

The twist-curled textured yarn has many desirable properties. It hasreduced shrinkage and, thus, has been stabilized against the tendency ofordinary twist-curled textured yarn to retract in length when fabricmade therefrom is heated during some stage of the production thereof.The yarn has greater bulk. For example, yarn heated by the presentinvention has from about 40-80% greater bulk as compared to similartwist-curled yarn which has not been treated by the multi-stage heatingand cooling process of the invention. The improved bulk is not obtainedat considerable sacrifice of stretch, and the yarn has good stretchcharacteristics. The yarn has the ability to accept a slightlongitudinally applied stretch and thereby to become easily extended aconsiderable length without permanent elongation thereof. For example,the yarn can be easily elongated from its untensioned or relaxed lengthand immediately recover from this elongation. The yarn is not renderedtorqueless by the treatment. It still has the tendency (although less)to produce a twisting in the individual threadlines to form kinks andcurls.

The following is an example of the above-described yarn treatment.Obviously the invention is not limited thereto.

Example The yarn used was prepared by melt spinning and cold drawingnylon-66. One end of 70 denier/ 34 filaments was false twisted so thatit had 76 S turns per inch. The twist was set by heating it to a surfacetemperature of 250 C. and cooling it after which the twist was released.A like end was Z-twist-curled textured. The two ends were plied togetherwith a ply twist of 0.5 turn per inch, and the plied yarn was wound on abobbin.

Apparatus corresponding to that in the attached drawing was used totreat the plied yarn. The Warn was unwound for treatment and passedthrough a pair of feed rolls at a speed of 511 yards per minute. Fromthe feed rolls the yarn was moved through a steaming zone to a pai-r ofwithdrawal rolls at a speed of 465 yards per minute. This yarn wascontacted with steam at 225 C. and exhibited a temperature as it exitedthe chamber of 120 C. The yarn was guided through the surroundingatmosphere back to the feed rolls. Thus, the yarn was stretched andcooled. Just before reaching the feed rolls the yarn had cooled to 27 C.Again the yarn was passed through the steaming chamber and through thesurroundings to the feed rolls for a third passage through the steamingchamber. After the third heat treatment the yarn was collected on aconventional ring twister assembly.

The yarn showed improved voluminosity and dimensional stability. Theskein shrinkage of the yarn by the treatment was reduced from 32 to 12%.The threadline volume was increased 140%. The yarn had a stretch of115%. The individual ends composing theyarn showed torsion. The denierof the finished yarn was 2.8% higher than that of the supply. The yarnhad an average elongation of 27% and the tenacity averaged 4.0 grams perdenier.

The advantages of the invention are many. The method results in themanufacture of twist-curled textured yarn having a favorable balance ofbulk and stretch. The device can be run at high speeds. The inherentproperties of the treated yarn are such that they impart numerous anddesirable properties in fabrics made therefrom.

. Many different embodiments of the invention may be made withoutdeparting from the spirit and scope thereof.

We claim:

1. Apparatus for treating twist-curled textured yarn comprising:

(a) means for feeding the yarn at a predetermined first speed;

(b) means for forwarding the yarn at a predetermined second slowerspeed;

(c) means between the feeding means and the forwarding means for heatingthe yarn;

((1) guide means for returning the yarn from the forwarding means to thefeeding means a plurality of times; and

(e) means for collecting the yarn in a uniform manner.

2. Apparatus for treating twist-curled yarn comprising:

(a) a first pair of nip-forming feed rolls for feeding the yarn from asource thereof at a predetermined first speed;

(b) a second pair of nip-forming feed rolls for forwarding the yarn at apredetermined slower speed to provide an overfeed of the yarn betweenthe two pairs of rolls;

(c) yarn heating means in the yarn path between the two pairs of rollsfor heating the overfed yarn;

(d) guide means for directing the yarn for subsequent reheating from thesecond pair of rolls back to the first pair of rolls in a path removedfrom the heating means and having a length sufficient to cool the yarn;and

(e) means for packaging the treated yarn.

3. Apparatus for treating twist-curled yarn compris- (a) a first pair ofnip-forming feed rolls, one of which is positively driven, for feedingthe yarn from a source thereof at a predetermined first speed;

(b) a second pair of nip-forming feed rolls, one of which is positivelydriven, for feeding the yarn at i a predetermined slower speed toprovide an overfeed of the yarn between the two pairs of rolls;

(c) a yarn heating chamber through which the yarn passes between the twopairs of rolls;

(d) means for supplying pressurized steam to said chamber for steamingthe yarn as the same moves therethrough;

(e) guide means for directing the yarn from the second pair of rollsback to the first pair of rolls in a path removed from the heatingchamber and having a length sufiicient to cool the yarn prior to beingpassed again through the heating chamber; and

(f) means for twisting and packaging the treated yarn.

4. Apparatus for treating twist-curled yarn comprismg:

(a) a first pair of nip-forming feed rolls, one of which is positivelydriven, for feeding the yarn from a source thereof at a predeterminedfirst speed;

(b) a second pair of nip-forming feed rolls, one of which is positivelydriven, for feeding the yarn at a predetermined slower speed to providean overfeed of the yarn between the two pairs of rolls;

(0) a yarn heating chamber through which the yarn passes between the twopairs of rolls;

'(d) means for supplying pressurized steam to said chamber for steamingthe yarn as the same moves therethrough;

(e) a first stationary guide spaced from the second pair of rolls;

(f) a second stationary guide spaced from the first pair of rolls, theguides providing a path removed from heating chamber to cool the yarnprior to being passed again through the heating chamber; and

(g) means for twisting and packaging the treated yarn.

References Cited UNITED STATES PATENTS FRANK J. COHEN, Primary Examiner.

D. WATKINS, Assistant Examiner.

